...SYNOPSIS... MODELS REMAIN CONSISTENT SHOWING BROAD UPPER TROUGH WILL PERSIST FROM THE LOWER MS AND OH VALLEYS THROUGH AREAS SOUTH AND EAST OF THE GULF AND SRN/MID ATLANTIC COASTS. WHILE A STRONGER DEEP CLOSED LOW MOVES AWAY FROM THE NRN ATLANTIC COAST...A WEAK TROUGH SHOULD TRACK SEWD FROM THE UPPER OH VALLEY TO THE MID ATLANTIC COAST ON DAY 2. FARTHER W/SW...A SHORTWAVE TROUGH CURRENTLY LOCATED OVER WI/NRN IL...WILL EVOLVE INTO A COMPACT CLOSED LOW AS IT MOVES SWD THROUGH THE MID SOUTH TO THE LOWER MS VALLEY/CENTRAL GULF COAST STATES.

UPPER RIDGING WILL REMAIN STRONG THROUGH FRIDAY FROM THE SOUTHERN PLAINS INTO THE UPPER MS VALLEY. SOME WEAKENING OF THIS RIDGE WILL LIKELY COMMENCE FRIDAY NIGHT INTO EARLY SATURDAY ACROSS THE CENTRAL AND NRN HIGH PLAINS AS THE LARGE-SCALE WESTERN U.S. UPPER TROUGH MOVES SLOWLY EWD ACROSS THE INTERMOUNTAIN WEST AND ROCKIES. THE MOST SIGNIFICANT EMBEDDED SHORT WAVE IMPULSE STILL APPEARS LIKELY TO REMAIN W OF THE CENTRAL ROCKIES THROUGH 12Z SATURDAY. HOWEVER...A LEAD IMPULSE/SPEED MAX WILL TRACK FROM THE BASE OF THE WRN TROUGH TO THE NRN HIGH PLAINS BY LATE FRIDAY. THIS IMPULSE MAY PHASE WITH SEVERAL WEAKER IMPULSES EMANATING FROM BAJA AND MEXICAN PLATEAU AND MOVING NNEWD THROUGH THE CENTRAL HIGH PLAINS TO DAKOTAS.

...SERN STATES... A MOIST AND MODERATELY UNSTABLE AIR MASS IS EXPECTED TO EXTEND FROM THE OH VALLEY TO THE OZARKS/SRN PLAINS AND EWD TO THE GULF COAST AND SRN/MID ATLANTIC STATES ON FRIDAY. TSTMS ARE EXPECTED TO DEVELOP ACROSS MUCH OF THIS REGION...WITH ACTIVITY LIKELY ENHANCED IN THE VICINITY OF A COUPLE WEAK SURFACE BOUNDARIES 1/ IN LEE OF THE SRN APPALACHIANS...AND 2/FROM THE UPPER OH TO UPPER TN VALLEYS. FORCING FOR ASCENT WITH THE UPPER OH VALLEY MID LEVEL TROUGH SHOULD SUPPORT GREATER STORM COVERAGE ALONG THESE TWO BOUNDARIES. THE SRN EXTENT OF SUFFICIENT EFFECTIVE BULK SHEAR /AROUND 30 KT/ FOR SOME STORM ORGANIZATION WILL EXTEND SWD INTO VA/ERN NC. ALTHOUGH SHEAR WILL BE WEAKER ELSEWHERE... DIVERGENT FLOW ALOFT IN LEE OF THE SRN APPALACHIANS CONTINUES TO ALSO SUPPORT MORE TSTM DEVELOPMENT IN THIS REGION. STRONG SURFACE HEATING/STEEPER LOW-LEVEL LAPSE RATES ACROSS THE SLIGHT RISK WILL PROVE FAVORABLE FOR DOWNBURSTS AND EVOLVING COLD POOLS ENHANCING THE THREAT FOR DAMAGING WIND GUSTS.